function DirectionsBase(){
	this.getFirst = function(){throw "Not Implemented!";};
	this.getLast = function(){throw "Not Implemented!";};
	this.getNext = function(theDirection){throw "Not Implemented!";};
	this.getPrevious = function(theDirection){throw "Not Implemented!";};
	this.getValues = function(){throw "Not Implemented!";};
	this.getOpposite = function(theDirection){throw "Not Implemented!";};
	this.getNextColumn = function(theStartColumn,theStartRow,theDirection){throw "Not Implemented!";};
	this.getNextRow = function(theStartColumn,theStartRow,theDirection){throw "Not Implemented!";};
}